Attachment for dental impression-trays.



3mm Mmcmald.

F. B. MAcDONALTL ATTACHMENT FOR DENTAL IMPRESSION TRAYS,

APPLICATION FILED APR. 7. I917.

FOSTER 13.1VIACDONALD, 0F HAZELTON, PENNSYLVANIA.

ATTACHMENT FOR DENTAL IMPRESSION-TBAYS.

Specification of Letters latent.

Patented Dec. I, I917.

Application filed April 7, 1917. Serial No. 160,492.

To all whom it may concern:

Be it known that I, Fos'rnn B. MAC- DONALD, a citizen of the United States, residing at I-Iazelton, in the county of Luzerne and State of Pennsylvania, have invented certain new and useful Improvements in Attachments for Dental Impression-Trays; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to an attachment for dental impression trays.

The object of the present invention is to provide a simple, practical and efiicient device adapted to be readily applied to dental impression trays and capable of effectually preventing the plaster of Paris, modeling compound or other impression material, in which the impressionis made, from entering the throat of the patient.

A further object of the invention is to provide a device of this character adapted to equalize the pressure of the impression, prevent buckling, eliminate ridges and enable a more accurate impression to be obtained.

Another object of the invention is to provide an attachment equipped with means for adjustably securing it to the handle of a dental impression tray and adapted to permit the latter to be held in the usual manner and to afford the necessary space to enable the operator to press his second finger directly against the impression tray in taking an impression so that the pressure will be directly upward and not lateral.

With these and other objects in view, the invention consists in the construction and novel combination of parts hereinafter fully described, illustrated in the accompanying drawing and pointed out in the claims hereto appended; it being understood that various changes in the form, proportion, size and minor details of construction, within the scope of the claims, may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawing:

Figure 1 is a plan view of a dental impression tray provided with an attachment and constructed in accordance with this invention.

Fig. 2 is a reverse plan view of the same.

Fig. 3 is a longitudinal sectional view of the tray and the attachment.

Fig. e is a transverse sectional view.

Fig. 5 is a detail view of the rear transverse plate.

Like numerals of reference designate corresponding parts in the several figures of the drawing.

In the accompanying drawing in which is illustrated the preferred embodiment of the invention, the attachment comprises in its construction a rear transverse plate 1, a supporting spring 2 and an adjustable sleeve 3. The supporting plate, which has oppositely inclined side portions, is approximately inverted V-shaped and it extends across the open back ofan impression tray i to form a rear wall thereof so as to hold the impression material in the tray while an impression is being made so as to secure a uniform pressure on the impression material and prevent any of the same from entering the throat of the patient. The rear plate, which conforms generally to the configuration of the rear edge of the impression tray and which may be of different sizes and forms to conform to the configuration of the mouth of the patient, is provided at its rear face with spaced vertical sleeves 5 for the reception of upturned terminal portions or arms 6 of a forked rear portion of the spring 2. The spring 2, which is constructed of steel wire or other suitable resilient material, consists of a single piece of the same bent centrally and brought together to form a shank 7 and the side portions of the wire at the inner end of the shank are spread or forked to form the sides or arms 8 which are spaced apart at the central longitudinal portion of the impression tray and which con verge at the front portion thereof, as clearly shown in Fig. 2 of the drawing. This provides ample space for the second finger of the operator to press against the bottom of the impression tray and exert a direct upward pressure when making an impression. The rear plate is supported by the resilient sides of the shank and it is provided at opposite sides with forwardly extending or inwardly extending lugs or prongs 9 which are located beneath the impression tray at opposite sides of the rear portion thereof to limit the upward movement of the rear plate and to steady the same and the said springs are adapted to permit the plate to yield and at the same time maintain the upper edge of the plate against the roof of the mouth so that the material will be effectually prevented from entering the throat of the patient. The shank 7 is arranged in an eye or sleeve 10 of a slide 11 arranged on the handle 12 of the impression tray and consisting of a flattened sleeve which is adjustable inwardly and outwardly along the handle to position the plate in proper relation with the impression tray. The slide, which embraces the handle 12, is provided with a plurality of springs 18 preferably formed integral with the slide by partially severing portions of the metal thereof, but they may be constructed in any other desired manner and any number of the springs may be employed, and other means may be substituted for the springs for adjustably securing the slide to the handle of the dental impression tray. The springs frictionally engage the upper face of the handle and maintain the slide in its adjustment.

What is claimed is:

1. An attachment for dental impression trays including a rear transversely disposed plate adapted to extend across the back of a dental impression tray for retaining the impression material therein, said plate being provided at opposite sides with inwardly extending lugs arranged to engage beneath s the dental impression tray, and means for yieldably supporting the said plate from the tray whereby the plate is adapted to be held against the roof of the mouth and maintained in such position while an impression is being made.

2. An attachment for dental impression trays including a rear transversely disposed plate adapted to extend across the back of a dental'impression tray for retaining the impression material therein, said plate being provided at opposite sides with inwardly extending lugs arranged to engage beneath the dental impression tray, and means for yieldably supporting the said plate from i the rear plate, and means for securing the spring to the handle of the tray.

4. An attachment for dental impression trays including a rear plate adapted to extend across the back of the tray, a longitudinal spring located beneath the tray and having spaced side portions connected with the rear plate, a slide consisting of a transverse flattened sleeve through which the handle of the tray passes, said slide being provided at its under side with an eye or sleeve receiving the said spring, said slide being also provided at its upper face with a plurality of springs engaging the handle to retain the slide in its adjustment.

In testimony whereof I affix my signature in presence of two witnesses.

FOSTER B. MACDONALD.

Witnesses:

Tnos. K. RICHARDS, G. J. MGLAUGHLIN.

Copies of this patent may be obtained for five cents each, by addressing the "Commissioner of Patents, Washington, D. 0." 

